Air Conditioning Flashcards
Each air conditioning pack are supplied pressurized and flow-regulated air by…
APU bleed.
a Ram Air Turbine (RAT).
two dedicated electric cabin air compressors (CACs).
engine or APU bleed.
two dedicated electric cabin air compressors (CACs).
Outside air is supplied to four electric cabin air compressors (CAC) through two dedicated inlets located in the wing to body fairings. The air is then pressurized and flow-regulated by the CACs and supplied to _____ air conditioning pack(s).
two identical
three identical
four identical
one
two identical
Normally, to maximize system efficiency, how many cabin air compressors (CACs) run when using the APU as the power source?
One on the left side.
Two on the right side.
One on each side.
All four.
One on each side.
A ground source of conditioned air may be used to supply conditioned air directly to the cabin distribution system, eliminating the need for pack operation.
True
False
True
If an overheat or significant pack fault is detected, the pack…
switches to standby mode.
continues to run until it is manually shut down.
switches to alternate cooling.
shuts down automatically and the EICAS advisory message PACK (L,R) is displayed.
shuts down automatically and the EICAS advisory message PACK (L,R) is displayed.
Cabin attendants can reduce outside airflow to the cabin based on…
the number of airplane occupants.
inside air temperature.
outside air temperature.
the setting of the CABIN TEMP on the flight deck air conditioning panel.
the number of airplane occupants.
Pack outlet temperature is controlled by the…
temperature zone requiring the warmest air.
trim air valve.
temperature zone requiring the coolest air.
pack valve controller
temperature zone requiring the coolest air.
What is the status of CACs and Packs during a normal engine start?
One CAC operates on each side. Both packs are commanded off.
Both CACs operate on each side. Both packs are commanded off.
All CACs are commanded off during the initial start sequence. Packs do not restart until at least two minutes after engine start sequence is initiated and engine is running.
All four CACs and both packs are fully operative during normal engine start.
All CACs are commanded off during the initial start sequence. Packs do not restart until at least two minutes after engine start sequence is initiated and engine is running.
Which of the following occurs during Standby Cooling Mode?
EICAS advisory message PACK MODE (L,R) is displayed.
STBY COOLING is displayed in amber on AIR synoptic.
Pack cooling capacity may be less than in normal mode.
All of the above are correct.
All of the above are correct.
Which of the following statements is correct when the right pack is operating in the standby cooling mode (left pack operating normally)?
The right pack automatically switches to high flow.
The right pack may shut down at higher altitudes.
The right pack cooling capacity may be less than in normal mode resulting in warm flight deck or cabin temperatures at lower altitudes.
There is no EICAS indication of either pack operating in the standby mode.
The right pack cooling capacity may be less than in normal mode resulting in warm flight deck or cabin temperatures at lower altitudes.
What cools the large motor power distribution system located in the aft E/E equipment compartment?
The Power Electronics Cooling System (PECS)
The Integrated Cooling System (ICS).
Conditioned air ducted from the passenger cabin.
The Miscellaneous Cooling System.
The Power Electronics Cooling System (PECS)
The Power Electronics Cooling System (PECS) is a liquid cooling system used to cool the large motor power distribution system. The large motor power distribution system is located in…
the aft E/E equipment compartment.
the wing to body fairings.
the temperature control compartment.
the Flight Deck equipment compartment.
the aft E/E equipment compartment.
Identify which statement about the operation of the pressurization system description is true.
In operation with the loss of pressurization, it is important that the flight crew close the outflow valves during descent.
In normal operation of the cruise mode, maximum cabin altitude is no more than 6000 feet.
Two seconds after touchdown, both outflow valves open to pressurize the cabin.
If cruise altitude is unavailable from the FMC in AUTO, the default cruise altitude is 41,000 feet.
In normal operation of the cruise mode, maximum cabin altitude is no more than 6000 feet.
Which statement is correct regarding bleed air?
Bleed air is supplied by the engines and is used only for hydraulic reservoir pressurization.
Bleed air is supplied by the engines and is used only for cabin pressure.
Bleed air is supplied by the engines and is used only for wing anti-ice.
Bleed air is supplied by the engines and is used only for engine core and inlet cowl anti-ice.
Bleed air is supplied by the engines and is used only for engine core and inlet cowl anti-ice.
Which statement about the Alternate Ventilation System is correct?
The Alternate Ventilation System provides an alternate means of ventilating the cabin and flight deck in the event both packs are inoperative.
When the airplane is not pressurized normally and the ALT VENT switch is ON, air is drawn from the aft outflow valve to the flight deck.
The Alternate Ventilation System provides air flow into the forward electronics bay when both air conditioning packs are off on the ground.
The ALT VENT switch is guarded to prevent selection, which could open the vent valve and depressurize the plane.
The Alternate Ventilation System provides an alternate means of ventilating the cabin and flight deck in the event both packs are inoperative.
The aft equipment cooling system provides cooling and ventilating air for the aft E/E equipment compartment and heating/ventilating air for the aft cargo compartment.
True
False
True
The aircraft is divided into how many temperature zones for air conditioning?
5
7
2
4
7
Two identical air conditioning packs are supplied pressurized air from…
four Cabin Air Compressors (CACs).
the bleed air system.
four Ram Air Fans.
APU bleed air.
four Cabin Air Compressors (CACs).
If one Cabin Air Compressor (CACs) fails its respective air conditioning pack will shut down.
True
False
False
Normally, to maximize system efficiency, only one CAC on each side runs when using __________ as the power source. During cold weather operations both CACs are commanded on.
the APU
PCA
external air
the right engine
the APU
For normal engine starts, how many Cabin Air Compressors (CACs) are commanded off during the initial start sequence?
one on the right side and one on the left.Cabin Air Compressor on the right side
one on the right side
one on the left side
all four
all four
For certain internal malfunctions, pack control automatically uses ___________ as a backup to normal mode.
standby cooling mode
alternate cooling mode
direct cooling mode
secondary cooling mode
standby cooling mode
If one pack is in standby cooling mode and the other pack is operating normally, the pack in standby cooling will shut down at lower altitudes and…
lower outside air temperatures.
higher outside air temperatures.
higher humidity conditions.
lower humidity conditions.
higher outside air temperatures.
The flight deck receives _________ conditioned outside air and the passenger cabin receives a mix of outside air and recirculated air.
75%
100%
50%
90%
100%
A passenger compartment dehumidification system operates automatically when…
the upper RECIRC FAN is ON.
FWD EQUIP COOLING is ON.
both RECIRC FANs are on.
electrical power is available.
electrical power is available.
Turning the recirculation fans off…
will result in an overheat condition in the passenger cabin.
will increase the amount of fresh air to the passenger cabin.
does not increase the amount of fresh air to the passenger cabin.
results in increased airflow.
does not increase the amount of fresh air to the passenger cabin.
The Alternate Ventilation System (AVS) provides an alternate means of ventilating the cabin and flight deck in the event both packs are inoperative.
True
False
True
Flight crew shoulder and foot heaters are available…
in flight only.
only with APU electrical power available.
on the ground only.
only with electrical power supplied by both engines.
in flight only.
The humidification system operates automatically during cruise when the HUMID switch is on and is automatically switched off approximately 1-1.5 hours prior to touch down.
True
False
True
The aft cargo compartment is heated but the compartment temperature is uncontrolled.
True
False
True
Which cargo compartment(s) are capable of carrying live animals?
Only the FWD
FWD and BULK
FWD and AFT
AFT and BULK
FWD and BULK
Bulk cargo compartment ventilation and heat is provided from cabin air passing through a supply fan and…
ventilation air from the cabin.
air from the right CAC.
in-line electric heater.
shoulder and foot heaters.
in-line electric heater.
The equipment cooling system uses a primary and backup supply fan. If the primary fan fails…
the equipment cooling system will shutdown.
the backup supply fan will operate if the FWD and AFT EQUIP COOLING switches are cycled OFF the ON.
the backup supply fan will operate automatically.
both flow sensors will fail.
the backup supply fan will operate automatically.
If the EICAS message PACK (L, R) is displayed, an attempt to restore pack operation may be made by pressing the AIR COND RESET switch.
True
False
True
Which of the following is true concerning pack operation in the “Standby Cooling” mode?
For certain internal malfunctions, pack control automatically uses standby cooling mode as a backup to normal mode.
If one pack is in standby cooling mode and the other pack is operating normally, the pack in standby cooling mode shuts down at lower altitudes and higher outside air temperatures when ambient conditions do not permit standby cooling.
Pack cooling capacity may be less than in normal mode and may result in warm flight deck or cabin temperatures at lower altitude.
All of the above.
All of the above
If the flight deck or cabin temperature selector is unavailable to the pack temperature controller, the pack temperature is regulated to…
achieve either the last temperature set or an average cabin temperature of 75°F.
keep pack outlet temperature within 20 degrees of TAT.
modulate to keep pack outlet temperature between 40°F and 110°F.
automatically shut down.
achieve either the last temperature set or an average cabin temperature of 75°F.
The cabin de-humidification system in the passenger compartment uses _______ to remove moisture from the compartment.
two moisture separators
three aux fans
two zonal dryers
two de-humidifiers
two zonal dryers
The Alternate Ventilation System (AVS) consists of a flight deck switch and a dedicated flush inlet valve and duct that delivers outside air flow downstream of the left pack outlet.
True
False
True
The Miscellaneous Equipment Cooling System operation is fully automatic and powered on whenever the airplane is powered.
True
False
True
When is APU bleed air supply primarily used?
There is no APU bleed air capability on the 787
Engine starting
Primarily during ground operations
In flight above 28,000 ft
There is no APU bleed air capability on the 787
On the ground with the forward equipment cooling system inoperative…
The EICAS advisory message EQUIP COOLING FWD is displayed.
The ground crew call horn will sound in the wheel well.
Both of the above are correct
None of the above.
Both of the above are correct
The Power Electronics Cooling System (PECS) consists of two independent cooling loops. Each loop has a single pump package which contains…
one cooling pump.
one liquid storage reservoir.
one large motor controller.
two fully redundant pumps.
two fully redundant pumps
The Miscellaneous Equipment Cooling System is fully automatic and is powered when…
the IFE switch s OFF.
both RECIRC FAN switches are in the OFF position.
the aircraft is powered.
when AFT EXT PWR switch is selected ON.
the aircraft is powered.
Two outflow valves regulate the discharge of cabin air. If one outflow valve fails…
the remaining outflow valve is capable of maintaining pressurization.
the cabin altitude is limited to 6,000 ft.
the Cabin Pressure Control System reverts to the MANUAL mode.
the cabin pressure relief valves will open.
the remaining outflow valve is capable of maintaining pressurization.
The pressurization system uses data from the ________ to calculate a cabin pressurization schedule.
AOA
TCP
GPS
FMC
FMC
If cruise altitude is unavailable from the FMC in AUTO, the default cruise altitude is 43,000 feet.
True
False
True
If landing altitude is unavailable from the FMC, and not set in MAN, the EICAS message LANDING ALTITUDE is displayed and the cabin altitude controller assumes a landing altitude of…
2,000 ft.
6,000 ft.
1,000 ft.
sea level.
2,000 ft.
If a depressurization event occurs, the outflow valves close to preserve cabin pressure. It is important that the flight crew __________ during the descent.
manually opens the outflow valves
switches to the automatic mode
does not attempt to manually close the outflow valves
switches to MANUAL pressurization
does not attempt to manually close the outflow valves
If the LANDING ALTITUDE selector is pulled out to the detent, pressurization system indications will…
be displayed on EICAS.
be displayed on the CDU scratch pad.
be removed from EICAS.
will not be available to be viewed by the flight crew.
be displayed on EICAS.
What are the uses of engine bleed air?
Wing anti-ice and stabilizer anti-ice
Pitot probe heat and wing anti-ice
TAT heat and static heat
Engine anti–ice and engine core heat
Engine anti–ice and engine core heat
When a pack overheat is detected, the pack…
will switch to standby mode.
flow rate is modulated to keep the pack outlet temperature low.
will automatically switches pack controllers.
will automatically shut down.
will automatically shut down.
How does the automatic pressurization system keep “pressure bumps” from occurring during takeoff?
After liftoff, the system supplies a small positive pressure for smooth cabin altitude transition.
The system supplies a small positive pressurization prior to rotation to cause a smooth cabin altitude transition to the cabin altitude climb schedule.
Positive pressure relief valves go full closed.
Negative pressure relief valves transition to the full open position.
The system supplies a small positive pressurization prior to rotation to cause a smooth cabin altitude transition to the cabin altitude climb schedule.
What is the PECS normal service level?
1.2 or above
.75
- 0
- 1 minimum
1.0
The Power Electronics Cooling System (PECS) requires a cool-down period following pack and hydraulic EMP shutdown to dissipate residual heat from the liquid cooled LRU’s.
True
False
True
Airflow to the packs is controlled by regulating the cabin air compressors (CACs). Which of the following are correct?
CAC output is increased automatically during high demand periods to compensate for a failed pack.
CAC output is selectable by the pilot.
CAC output is limited during electrical load shed conditions to ensure sufficient electrical power is available to other critical systems.
Answers 1 and 3 are both correct.
Answers 1 and 3 are both correct.
With APU as the sole source of electrical power on the ground and both pack switches in AUTO, how many Cabin Air Compressors (CACs) are normally operating?
4
1
2
3
2
